Correct if in mapping example

We want to know if the memory is mappable, which means that the memory properties should include the `VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT`.
diff --git a/src/vk_mem_alloc.h b/src/vk_mem_alloc.h
index 20e978b..893c6b2 100644
--- a/src/vk_mem_alloc.h
+++ b/src/vk_mem_alloc.h
@@ -478,7 +478,7 @@
 

 VkMemoryPropertyFlags memFlags;

 vmaGetMemoryTypeProperties(allocator, allocInfo.memoryType, &memFlags);

-if((memFlags & VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT) == 0)

+if((memFlags & VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT) != 0)

 {

     // Allocation ended up in mappable memory. You can map it and access it directly.

     void* mappedData;